SQL operations page not included in the nav

[sumeshpremraj]

The SQL operations document is in the repo but not added to the nav, throwing up this log during build:

$ mkdocs build
INFO     -  Cleaning site directory
INFO     -  Building documentation to directory: /Users/spremraj/code/school-of-sre/site
INFO     -  The following pages exist in the docs directory, but are not included in the "nav" configuration:
              - level101/databases_sql/operations.md